trivial improvements (#105)

* set CMAKE_BUILD_PARALLEL_LEVEL before configuring
just in case some monster decides to build from within the configuration step (cough cough aws-c-cal/cmake/modules/aws-lc.cmake)

* more natural traversal order

builder/actions/cmake.py

@@ -108,13 +108,13 @@ def _build_project(env, project, cmake_extra, build_tests=False):
         with open(toolchain.env_file, 'a') as f:
             f.writelines(build_env)
 
-    # configure
-    sh.exec(*toolchain.shell_env, cmake, cmake_args, check=True)
-
     # set parallism via env var (cmake's --parallel CLI option doesn't exist until 3.12)
     if os.environ.get('CMAKE_BUILD_PARALLEL_LEVEL') is None:
         sh.setenv('CMAKE_BUILD_PARALLEL_LEVEL', str(os.cpu_count()))
 
+    # configure
+    sh.exec(*toolchain.shell_env, cmake, cmake_args, check=True)
+
     # build
     sh.exec(*toolchain.shell_env, cmake, "--build", project_build_dir, "--config",
             build_config, check=True)

builder/core/project.py

@@ -596,20 +596,16 @@ def get_flattened_dependencies(self, spec, *, include_self=False):
         Gets full tree of dependencies as flat list with duplicates removed.
         Items are ordered such that building Projects in the order given should just work.
         """
-        # first, gather flat list of deps, in breadth-first order, with duplicates included
-        def _gather_all(project, spec):
-            deps = project.get_dependencies(spec)
-            for dep in deps.copy():
-                deps += _gather_all(dep, spec)
-            return deps
-
-        all_deps = _gather_all(self, spec)
-        if include_self:
-            all_deps.insert(0, self)
-
-        # remove duplicates and put everything in proper build-order
-        unique_deps = UniqueList(reversed(all_deps))
-        return unique_deps
+
+        # each project inserts dependencies before self
+        def _post_order(project, spec, deps):
+            for dep in project.get_dependencies(spec):
+                _post_order(dep, spec, deps)
+            deps.append(project)
+
+        deps = UniqueList()
+        _post_order(self, spec, deps)
+        return deps
 
     def get_consumers(self, spec):
         """ Gets consumers for a given BuildSpec, filters by target """